I would suggest these slides with less text and more diagrams/charts:
1. Slide with a logo, tagline, and a quote from someone about the company/product or a vision statement
2. Team - highlight relevant experiences, skills, and expertise
3-4 Problem/Solution fit for your product - 1 slide describing problem and how it's solved now, next slide how your product/services solves the problem. Note why you want to tackle this problem and why now.
5. Competitors and how you are different from them or if the product is new list companies that are similar and/or those you might be getting a market share from. A venn diagram showing an overlap of markets (and companies in those markets) that create your market is great for this. This slide shows you have done your leg work and understand how/where your product fits into the marketplace.
6. Traction - any stats you have to-date, and roadmap for getting users. If pre-launch, info on MVP and vision for launch.
7. Business Model. List ways you can make money
8. Summary and Takeaways.
There are a lot of pitch decks and templates shared online, the biggest difference is the company stage and what you have to highlight (metrics, user acquisition channels, etc.). The number of slides will vary dramatically, but I was told by an experienced Angel investor (in a class setting) to keep it under 10 slides - less is more.
There's really no one answer, given that angels vary widely in their sophistication level. Some angels want to just meet and talk with you while others may want 40 page powerpoint slides that are actually word documents in disguise.
With that in mind, here are some general ideas. I'm taking the approach of several different deliverables so you can share the right level of detail with the right kind of angel (in other words, you wouldn't necessarily want to give an angel all of this information).
Hope this helps!